Throat plate for sewing machines



Nov. 15, 1949 FISCHBEIN I 2,488,390

THROAT PLATE FOR SEWING MACHINES Original Filed Aug. 29, 1945 Patented Nov. 15, 1949 UNITED STATES PATENT OFFICE 2,488,398 THROAT PLATE FOR SEWING MACHINES Dave Fischbein, Minneapolis,

Original application August 29, 1945, .Serial No. 613,261. Divided and this application August 19, 1946, Serial No. 691,465

My present invention relates to improvements in sewing machines and more particularly to a novel throat plate therefor.

This invention is "a division of my co-pending application entitled, Electric sewing machine, filed August 29, 1945, under Serial No. 613,261 now Patent No. 2,484,495, dated October 11, 1949.

The object of this invention is to facilitate chaining at the completion of the closing of the mouth of a filled bag by sewing. It may be here stated that "chaining is the continuation of forming stitches by sewing after the material being sewed has been fed past the needle and said needle is no longer operating in a material. The purpose of chaining, at the completion of closing the mouth of a filled bag by sewing, is to prevent the stitches from unravelling. Or in other words, chaining acts as a tie or knot in the thread at the completion of a sewing operation.

Other objects of the invention will be apparent from the following description, reference being had to the drawings.

To the above end, the invention consists of the novel construction and arrangement hereinafter described and defined in the claim.

In the accompanying drawings, which illustrate the invention, like characters indicate like parts throughout the several views.

Referring to the drawings:

Fig. 1 is a fragmentary view principally in section showing an electric sewing machine having the invention embodied therein;

Fig. 2 is a fragmentary view partly in plan and partly in section taken on the irregular line 2-2 of Fig. 1;

Fig. 3 is a fragmentary detail view principally in section taken on the line 3-3 of Fig. 1, on an enlarged scale;

Fig. 4 is a fragmentary view of the throat plate as shown in Fig. 3; and

Fig. 5 is .a view of the throat plate shown in Fig. 4. turned over to show the back thereof.

Of the parts of the electric sewing machine illustrated in the drawings it is important to note the housing 6 having a feed passageway I for the top portion of a filled bag to be closed by sewing, an upright driven shaft 8 having on its lower end the customary hook 9 having a heel l8.

Feed dogs operating in upper and lower slots l2 in a throat plate I3 which is the subject matter of my resent invention. These feed dogs II are actuated by a feed bar M which receives its motion from an ecc ntric IS on the shaft 8. The feed bar I4 is carried by a rocker frame I6.

1 Claim. (Cl. 112-260) A reciprocal needle bar I! is mounted in a bearing l8 on the housing 6. Mounted in the inner end portion of the needle bar I! is a needle IS. In the rear end portion of the needle bar I! is a passageway 28 for sewing thread X. The needle bar I! is reciprocated by a lever 2|, fragmentarily shown, and receives its motion from the shaft 8 through suitable connections, not shown.

Cooperating with the feed dogs I l is a pressure foot 22 pivoted on the inner end of the bar 23, fragmentarily shown. This bar is yieldingly pressed toward the feed dogs II by a spring, not shown.

On the back of the throat plate I3 is a chainforming guide block 24 having a thread supporting lip extension 25. A thread-receiving slot 26, an inner recess 21 and an outer recess 28 are spaced from the needle hole 29 and from each other in the order given, in the direction of the feeding of the machine to its work. The threadreceiving slot '26 extends through the throat plate 13 and the block 24, the inner recess 21 extends through the block 24 and the outer recess 28 extends through the throat plate l3 to the block 24. The thread-receiving slot 26 leads from the needle hole 29 to the inner recess 21 and the outer recess 28 is in communication with the thread-receiving slot 26 and the inner recess 21. The block 24, at the inner recess 21, is countersunk, as indicated at 38. It is important to note that the outer recess 28 projects beyond the inner recess 21 in provision of a thre'ad-chain-receiving chamber 28'.

The lip extension 25, over which the needle 29 extends when projected, prevents the thread X from dropping downwardly from the needle I9 into a position in which the hook 9 would not pick up said thread, when it passes over the needle 29, by entering the loop formed at the needles eye. 7

It may be assumed that the last stitch has been made in a bag and the needle I9, during the next stitch-forming cycle, does not pass through the material and starts the formation of a chain. The first stitch in the chain will be between the needle 19 and the counter-sink 38. During the next cycle of operation, the first stitch will be drawn into the inner recess 21 and the wall of said inner recess, farthest from the needle l9, holds the thread X in a forward position to enable the heel III to enter the triangle formed in the thread during the stitch-forming cycle. The first stitch during the next cycle of operation will be drawn into the outer recess 28 to be out the needle I9 and each other and their severai'.

functions :are highly important to the successful chaining operation of the machine.

From what has been said, it will be understood that the invention described is capable of modifications as to details of constructionand arrangement within the scope of the invention herein disclosed and claimed.

What I claim is:

In a sewing machine, a throat plate provided 0 with an elongated thread-receiving slot having a needle hole at one end thereof and terminating at its opposite end in 'an inner recess and an outer recess opening through the inner and outer walls of the plate, said outer recess projecting beyond the inner recess in a direction away from the needle hole in the provision of a thread chain receiving chamber.

DAVE FISCHBEIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 158,214 Huntington Dec. 29, 1874 863,491 Ammerman' Aug. 13, 1907 2,350,267 Zonis May 30, 1944 

